Mechanic working in auto repair shop.
WSG data revealing the top 10 most common LCV warranty claims highlighted alternators as the biggest issue, accounting for 5.35% of all claims and costing on average £506.78 per repair.
Engine-related problems are the costliest and most common cause of claims. The highest-value LCV warranty claim in 2025 was for a Mercedes Sprinter 316 CDI, with a significant engine-related claim valued at over £6,000.
Mark Bobbins, Head of Commercial Vehicle Sales at WSG, said: “Repair data tells a compelling story about real-world reliability – and some LCV brands consistently hit fleets harder in the pocket when things go wrong.
“What we’re seeing is a growing pattern: emissions-related components like NOx sensors, EGR valves, and AdBlue injectors are not just expensive to replace, they’re also failing more often. This isn’t just a technical issue – it’s a financial one.
“With environmental regulations tightening and vehicle systems becoming more complex, the cost of non-maintenance is rising fast. Proactive servicing and strong warranty support are no longer optional, they’re essential for managing risk and maintaining fleet uptime.”
Interestingly, claim values for the top 10 ranged from £2,500 to just over £6,000, with many hitting the cap imposed by warranty limits.
Bobbins said: “In the current economic climate, one major repair can knock profitability off course. That’s why understanding which parts fail most, and planning accordingly, can make a measurable difference to a fleet’s bottom line.
“Our live claims data helps operators make smarter decisions about vehicle selection, servicing, and protection.”
WSG also released data on the UK’s most reliable convertible in 2025.
The Mazda MX-5 is the UK’s most reliable convertible in 2025, according to WSG research based on a sample of 3,000 extended warranty claims paid by the firm between July 2025 and June 2025.
With a claim rate of 7.69%, the Mazda MX-5 takes the top spot for its dependability.
The vehicle is known for its low-maintenance engine and it is considered more reliable than many more expensive marques.